Fuel composition for fuel cells

A hydride containing fuel composition for a liquid fuel cell, wherein the composition comprises an alkaline liquid phase and at least a first hydride compound and a second hydride compound and wherein a solubility of the first hydride compound in the liquid phase is higher than a solubility of the second hydride compound in the liquid phase and a solubility of an anodic oxidation product of the first hydride compound in the liquid phase is lower than a solubility of an anodic oxidation product of the second hydride compound in the liquid phase, said alkaline liquid phase having a hydroxide ion concentration of at least about 0.5 mole per liter and comprising dissolved therein one or more of LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Mg(OH)2, Ba(OH)2, Zn(OH)2, Al(OH)3 and NH4OH, and said first hydride compound and said second hydride compound being independently selected from NaBH4, KBH4, LiBH4, NH4BH4, Be(BH4)2, Ca(BH4)2, Mg(BH4)2, Zn(BH4)2, Al(BH4)3, polyborohydrides, (CH3)3NBH3, NaCNBH3, LiH, NaH, KH, CaH2, BeH2, MgH2, NaAlH4, LiAlH4 and KAlH4.

A hydride containing fuel composition for a direct liquid fuel cell, wherein the composition comprises at least two different hydride compounds, the at least two different hydride compounds being such that the composition provides a higher efficiency than an otherwise identical fuel composition that comprises only one of the these different hydride compounds in a molar amount which is identical with a total molar amount of the at least two different hydride compounds.

A method of increasing the fuel efficiency of a hydride compound containing liquid fuel composition for a direct liquid fuel cell, wherein the method comprises employing at least two different hydride compounds in the fuel composition, the at least two different hydride compounds being selected such that a fuel composition comprising the at least two different hydride compounds has a higher efficiency than an otherwise identical fuel composition which comprises only one of the at least two different hydride compounds in a molar amount which is identical with a total molar amount of the at least two different hydride compounds.

A method of improving the performance of a liquid fuel cell which comprises a hydride compound containing liquid fuel composition, wherein the method comprises employing at least two different hydride compounds in the liquid fuel composition, the at least two different hydride compounds being selected such that the fuel composition comprising the at least two different hydride compounds is chemically less aggressive toward at least one structural component of the fuel cell than, and shows at least the same efficiency as a liquid fuel composition which comprises only one of these hydride compounds in a molar amount which is identical with a total molar amount of the at least two different hydride compounds.